1. Field of the Invention
This invention relates to a distributor for igniting a combustion engine which can prevent backlash from being caused between a first gear rotating in synchronism with a crank shaft of the combustion engine and a second gear meshed with the first gear.
2. Related Art
FIG. 17 is a sectional view showing a main portion of an exemplary conventional distributor for igniting a combustion engine. In FIG. 17, reference numeral 1 designates a housing; 2, a rotating shaft rotatably supported by the housing 1 through a sleeve 3 and a, bearing 4, one end of which is projecting toward outside from the housing 1; 5, a fixed helical gear which is inserted into the rotating shaft 2 projecting toward outside and which is held by a pin 6; and 7, a crossed helical gear which is meshed with the fixed gear 5 and which rotates in synchronism with a crank shaft (not shown) of the combustion engine.
In the distributor for igniting a combustion engine thus constructed, the rotating shaft 2 rotates in synchronism with the rotation of the crank shaft through the crossed helical gear 7 and the fixed gear 5, thereby determining the firing timing and the like.
In the conventional distributor for igniting a combustion engine thus constructed, a certain amount of backlash is provided between the teeth of the crossed helical gear 7 and the fixed gear 5 to accommodate fabrication errors and mounting tolerances of the gears, and this backlash has caused undesirable effects such as unstable firing timings and excessive spark advances due to free rotation of the fixed gear 5, the rotating shaft 2, and the like with respect to the crossed helical gear 7 within the backlash assisted by their moment of inertia.
As measures to this problem, a shifted gear may be introduced or gear accuracy may be improved in attempts to reduce the backlash. However, these measures are not successful in completely eliminating the backlash. Rather, a smaller backlash causes seizure and wear, thus impairing the reliability.